Water & Wastewater

Chemainus’s drinking water is supplied from two sources, depending on the time of year: Holyoak Lake and the Chemainus aquifer. Water from both systems is chlorinated and monitored for turbidity and residual chlorine to ensure the levels are within provincial regulations.

From mid-October to mid-June, drinking water is supplied from of the Chemainus aquifer via two wells and a pump station/chlorination station. The wells and station are located just east of the Chemainus River Bridge on Hwy 1. The ground water is extracted at 68 l/sec.

NOTE: North Cowichan has received a two-year permit from the Ministry of Forests, Lands and Natural Resource Operations (MoFLNRO) to allow usage of the wells between June 15 and October 15. The permit has been issued to allow for some testing to determine what, if any impacts, pumping will have on the Chemainus River.

From June 15 to October 15, water is supplied from Holyoak Lake. Holyoak Lake is the headwaters for Banon Creek. Holyoak Lake has two dams: an earth embankment at the south with a smaller earth embankment dam and a concrete dam structure at the north end. The catchment area is approximately 138 ha (341 ac).

During periods of low flow in West Banon Creek, the concrete dam’s 600 mm (24”) slide gate is adjusted to provide measured supplemental water flow into the creek.

The discharge is measured by a weir and flow releases are measured to meet community demand. The Banon Creek reservoir, dam, and intake for the Chemainus Water System are located on West Banon Creek, approximately 10 km downstream of Holyoak Dam.

Water from the surrounding catchment area, which includes Holyoak Lake, flows to two 2,000,000 L concrete reservoirs located on the Copper Canyon Haul Road before supplying the town.

A permit issued by Island Health requires that no water with a turbidity greater than 1 Nephlometric Turbidity Units (NTU) is to be let into the system without a notification to Island Health. Chlorine residual must be maintained at a minimum of 0.2 mg/L at all points in the system. 

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Banon Creek dam at Holyoak Lake

Distribution System

Chemainus’ topography means the distribution system is divided into two pressure zones by utilizing 5 mainline pressure reducing stations and 350 household pressure reducing valves located at each household service. Pipe types range from cast iron, asbestos cement, PVC and ductile iron and replacement is done on an ongoing basis, and considers pipe age, material, failure rate, and water quality issues

Crofton’s drinking water comes from two different sources. Which source you are on depends on your address.

For the lower pressure zone water is from a surface water source (the Cowichan River) and is supplied in bulk from the Paper Excellence’s Water Treatment Plant (WTP) located at the end of Mann Street.

The water is extracted from the Cowichan River and pumped to the WTP where it undergoes sedimentation, filtration and chlorination. Seasonally the addition of Aluminum Sulfate (coagulant) is required to settle out the fine solids in the sedimentation process located ahead of  the filtration process.

Additional chlorination is done by North Cowichan to satisfy the provincial treatment requirements for surface water.

For the upper pressure zone water is from a ground water source (the Cowichan River aquifer) and is supplied in bulk from North Cowichan’s South End supply via the newly built Osborne Bay Rd water pump station.

The permit issued by Island Health requires that no water with a turbidity greater than 1 Nephlometric Turbidity Units (NTU) is to be let into the system without notification to Vancouver Island Health Authority. Chlorine residual must be a minimum of 0.2 mg/L at all points in the system.

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The South End of North Cowichan is supplied with drinking water from Cowichan River aquifer. The wells and pump station/treatment station is located off Boys Rd, south of the Cowichan River and east of the Trans-Canada Highway. The water is disinfected using ultraviolet light followed by a small dose of chlorine for residual protection in the distribution system.

The water is monitored for turbidity  and chlorine levels to ensure they stay within provincial regulations.

The permit requires that no water with a turbidity greater than 1 Nephlometric Turbidity Units (NTU) is to be let into the system without notification to Island Health. The chlorine residual must be a minimum of 0.2 mg/L at all points in the system.

Cowichan Lake Weir

Catalyst Paper Corporate (Paper Excellence) constructed a weir at the mouth of Lake Cowichan in the 1950s in order to support the mill’s water needs. A need to update or redesign the weir due to lower summer flows on the Cowichan River was identified in the early 2000s and more recently a partnership was formed by the Cowichan Valley Regional District, Cowichan Tribes, the Cowichan Watershed Board, and Catalyst Paper to review these needs. More information about this work can be found at cowichanlakeweir.ca 

• While North Cowichan does not have a direct role in the weir, support is provided through the CVRD in efforts to raise the weir height. A raised weir would support water supply to Crofton, which is supplied via Paper Excellence, and to a lesser degree to South End water users, which is supplied via an aquifer that may be subjected to restrictions if water levels in the Cowichan River get too low. The Joint Utility Board water treatment plant requires water in the Cowichan River to treat effluent dilution requirements, in order to support a sustainable ecological river system.